/*
* Searches correct position for value on leaf page.
* Page should be corrrectly choosen.
* Returns true if value found on page.
*/
static bool
entryLocateLeafEntry(GinBtree btree, GinBtreeStack *stack)
{
Page page = BufferGetPage(stack->buffer);
OffsetNumber low,
high;
IndexTuple itup;
Assert(GinPageIsLeaf(page));
Assert(!GinPageIsData(page));
if (btree->fullScan)
{
stack->off = FirstOffsetNumber;
return TRUE;
}
low = FirstOffsetNumber;
high = PageGetMaxOffsetNumber(page);
if (high < low)
{
stack->off = FirstOffsetNumber;
return false;
}
high++;
while (high > low)
{
OffsetNumber mid = low + ((high - low) / 2);
int result;
itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, mid));
result = ginCompareAttEntries(btree->ginstate,
btree->entryAttnum,
btree->entryValue,
gintuple_get_attrnum(btree->ginstate, itup),
gin_index_getattr(btree->ginstate, itup));
if (result == 0)
{
stack->off = mid;
return true;
}
else if (result > 0)
low = mid + 1;
else
high = mid;
}
stack->off = high;
return false;
}
/*
* Adds array of item pointers to tuple's posting list or
* creates posting tree and tuple pointed to tree in a case
* of not enough space. Max size of tuple is defined in
* GinFormTuple().
*/
static IndexTuple
addItemPointersToTuple(Relation index, GinState *ginstate,
GinBtreeStack *stack, IndexTuple old,
ItemPointerData *items, uint32 nitem,
GinStatsData *buildStats)
{
Datum key = gin_index_getattr(ginstate, old);
OffsetNumber attnum = gintuple_get_attrnum(ginstate, old);
IndexTuple res = GinFormTuple(index, ginstate, attnum, key,
NULL, nitem + GinGetNPosting(old),
false);
if (res)
{
/* good, small enough */
uint32 newnitem;
newnitem = ginMergeItemPointers(GinGetPosting(res),
GinGetPosting(old),
GinGetNPosting(old),
items, nitem);
/* merge might have eliminated some duplicate items */
GinShortenTuple(res, newnitem);
}
else
{
BlockNumber postingRoot;
GinPostingTreeScan *gdi;
/* posting list becomes big, so we need to make posting's tree */
res = GinFormTuple(index, ginstate, attnum, key, NULL, 0, true);
postingRoot = createPostingTree(index, GinGetPosting(old), GinGetNPosting(old));
GinSetPostingTree(res, postingRoot);
gdi = ginPrepareScanPostingTree(index, postingRoot, FALSE);
gdi->btree.isBuild = (buildStats != NULL);
ginInsertItemPointer(gdi, items, nitem, buildStats);
pfree(gdi);
/* During index build, count the newly-added data page */
if (buildStats)
buildStats->nDataPages++;
}
return res;
}
static bool
entryIsMoveRight(GinBtree btree, Page page)
{
IndexTuple itup;
if (GinPageRightMost(page))
return FALSE;
itup = getRightMostTuple(page);
if (compareAttEntries(btree->ginstate,
btree->entryAttnum, btree->entryValue,
gintuple_get_attrnum(btree->ginstate, itup),
gin_index_getattr(btree->ginstate, itup)) > 0)
return TRUE;
return FALSE;
}
/*
* returns modified page or NULL if page isn't modified.
* Function works with original page until first change is occurred,
* then page is copied into temporary one.
*/
static Page
ginVacuumEntryPage(GinVacuumState *gvs, Buffer buffer, BlockNumber *roots, uint32 *nroot)
{
Page origpage = BufferGetPage(buffer),
tmppage;
OffsetNumber i,
maxoff = PageGetMaxOffsetNumber(origpage);
tmppage = origpage;
*nroot = 0;
for (i = FirstOffsetNumber; i <= maxoff; i++)
{
IndexTuple itup = (IndexTuple) PageGetItem(tmppage, PageGetItemId(tmppage, i));
if (GinIsPostingTree(itup))
{
/*
* store posting tree's roots for further processing, we can't
* vacuum it just now due to risk of deadlocks with scans/inserts
*/
roots[*nroot] = GinItemPointerGetBlockNumber(&itup->t_tid);
(*nroot)++;
}
else if (GinGetNPosting(itup) > 0)
{
/*
* if we already create temporary page, we will make changes in
* place
*/
ItemPointerData *cleaned = (tmppage == origpage) ? NULL : GinGetPosting(itup);
uint32 newN = ginVacuumPostingList(gvs, GinGetPosting(itup), GinGetNPosting(itup), &cleaned);
if (GinGetNPosting(itup) != newN)
{
Datum value;
OffsetNumber attnum;
/*
* Some ItemPointers was deleted, so we should remake our
* tuple
*/
if (tmppage == origpage)
{
/*
* On first difference we create temporary page in memory
* and copies content in to it.
*/
tmppage = PageGetTempPageCopy(origpage);
if (newN > 0)
{
Size pos = ((char *) GinGetPosting(itup)) - ((char *) origpage);
memcpy(tmppage + pos, cleaned, sizeof(ItemPointerData) * newN);
}
pfree(cleaned);
/* set itup pointer to new page */
itup = (IndexTuple) PageGetItem(tmppage, PageGetItemId(tmppage, i));
}
value = gin_index_getattr(&gvs->ginstate, itup);
attnum = gintuple_get_attrnum(&gvs->ginstate, itup);
itup = GinFormTuple(gvs->index, &gvs->ginstate, attnum, value,
GinGetPosting(itup), newN, true);
PageIndexTupleDelete(tmppage, i);
if (PageAddItem(tmppage, (Item) itup, IndexTupleSize(itup), i, false, false) != i)
elog(ERROR, "failed to add item to index page in \"%s\"",
RelationGetRelationName(gvs->index));
pfree(itup);
}
}
}
return (tmppage == origpage) ? NULL : tmppage;
}
/*
* Find correct tuple in non-leaf page. It supposed that
* page correctly choosen and searching value SHOULD be on page
*/
static BlockNumber
entryLocateEntry(GinBtree btree, GinBtreeStack *stack)
{
OffsetNumber low,
high,
maxoff;
IndexTuple itup = NULL;
int result;
Page page = BufferGetPage(stack->buffer);
Assert(!GinPageIsLeaf(page));
Assert(!GinPageIsData(page));
if (btree->fullScan)
{
stack->off = FirstOffsetNumber;
stack->predictNumber *= PageGetMaxOffsetNumber(page);
return btree->getLeftMostPage(btree, page);
}
low = FirstOffsetNumber;
maxoff = high = PageGetMaxOffsetNumber(page);
Assert(high >= low);
high++;
while (high > low)
{
OffsetNumber mid = low + ((high - low) / 2);
if (mid == maxoff && GinPageRightMost(page))
/* Right infinity */
result = -1;
else
{
itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, mid));
result = compareAttEntries(btree->ginstate,
btree->entryAttnum, btree->entryValue,
gintuple_get_attrnum(btree->ginstate, itup),
gin_index_getattr(btree->ginstate, itup));
}
if (result == 0)
{
stack->off = mid;
Assert(GinItemPointerGetBlockNumber(&(itup)->t_tid) != GIN_ROOT_BLKNO);
return GinItemPointerGetBlockNumber(&(itup)->t_tid);
}
else if (result > 0)
low = mid + 1;
else
high = mid;
}
Assert(high >= FirstOffsetNumber && high <= maxoff);
stack->off = high;
itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, high));
Assert(GinItemPointerGetBlockNumber(&(itup)->t_tid) != GIN_ROOT_BLKNO);
return GinItemPointerGetBlockNumber(&(itup)->t_tid);
}
